Looking Up: Leo, the king of spring

Friday

Mar 18, 2011 at 12:01 AMMar 18, 2011 at 6:11 PM

If you’ve never seen a lion leaping, tonight is your chance, should skies be clear. This virtual king of beasts is none other than the constellation Leo the lion. Predominant in the spring evening sky, Leo is already making its appearance as the spring equinox arrives March 20.

Peter Becker

If you’ve never seen a lion leaping, tonight is your chance, should skies be clear. This virtual king of beasts is none other than the constellation Leo the lion. Predominant in the spring evening sky, Leo is already making its appearance as the spring equinox arrives March 20.

Yes, like it or not, spring is finally beginning. This is the time when the length of day and night even out, and alas, nights are shorter than the days. Of course we all enjoy the light and warmth of our own special star, the sun, a few hours longer than winter would give. The night season may be shorter but well worth staying up later to see the dome of stars spread out over your house.

Those stars include several signs of spring, as sure and even more so, than the welcome sound of honking geese coming back, robins visiting the yard, taxes coming due and our springtime rite of taking off our snow tires and stowing away our snow shovels.

Leo the lion is definitely the king of spring, as he leads the pack of spring’s constellations. Others rising in the east this time of year include Virgo the virgin; Coma Berenices, Berenices’ hair; Bootes the herdsman; Hydra the water serpent; Sextans the sextant; Leo’s sidekick, Leo minor, the little lion; and of course Ursa major, the great bear, carrying the stars of the Big Dipper high in the northeastern sky.

Our imaginative forebears put these constellations together, most of them thousands of years ago. Leo is very ancient. The early Egyptians revered Leo because the Nile inundation occurred in those days, when the sun entered the constellation. Some believe that the sphinx represents Virgo’s head on Leo’s body.

The brightest star in Leo marks the lion’s courageous heart. It is officially known as Alpha Leonis, but his friends call him Regulus. The early Persians regarded Regulus as one of the four guardian stars of heaven, along with Fomalhaut, Aldebaran and Antares - each prominent in a differing season.

Regulus glows at magnitude +1.3 and appears bluish-white. The star is 77.5 light years away. It has an +8th magnitude companion star, visible in small telescopes. Each of them are themselves doubles, making this a quartet.

The star is very close to the ecliptic line, where the sun appears to travel and most of the planets and moon follow closely. The moon occasionally is seen passing in front of Regulus. Venus last eclipsed (“occulted”) Regulus in 1959 and will not do so again until 2044.

The forward part of Leo, or stars on the western side, can be imagined as a sickle, or a backward question mark, with Regulus marking the dot on the bottom. Among these stars is another that is fairly bright, Gamma Leonis or Algeiba. This is a beautiful double star visible in small telescopes. It is seen most easily in moonlight or in twilight. The colors of this close pair appear yellow and green. On the far eastern end is a fairly bright star, representing the tuft in Leo’s tai. This is Beta Leonis, or Denebola.

If you use a small telescope (or larger), be sure to sweep the area for galaxies. There are a couple notable ones, close together and visible in binoculars on a dark night if held very steady and aided by a good chart. They are labeled as M66 and M65. There’s a slightly fainter galaxy close by, seen in small telescopes, making it a neat triangle of galaxies.

Just west of Regulus a notable variable star, R Leonis, which changes from +5th magnitude (just seen with unaided eyes on a dark night) to a dim +11th magnitude.

The time it takes to swing between these extremes is 313 days.

Every November, the Leonid meteor shower swarms from Leo. On most years there are few in number, but every 33 years or so, they have been known to cascade by the hundreds and even thousands an hour.